I would not use a UV, it really does nothing for the pic, and will degrade them. If you want to protect your lenses, get a high quality one. I use circular polarizing filters all the time, they can be used to make the sky more blue, if you shoot perpendicular to the sun. They are also good for decreasing reflection or increasing it depending on the position you set it. But they do reduce the amount of light getting into the camera by about 3 fstops. So only use them on a sunny day.

C-pl I would get a hoya, or tiffen. BW are really good but very expensive like the tiffen HT series